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Author: Subject: Can someone guide me from chloride > perchlorate cell?
KonkreteRocketry
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[*] posted on 4-4-2013 at 03:20
Can someone guide me from chloride > perchlorate cell?


I got a charger from a broken printer with 20 Volts, and 4.6 Amps.

I can make it around 0.2 Amps per cm2, of water. I have few questions.

I saw Lead Dioxide, Platinum, Manganese Dioxide can be used, will it corrode ? I got plenty powdered Manganese dioxide from carbon batteries, so how shall i pack it into a like.. piece of solid thing to make it work ?

and. how much NaCl shall i put ?

Also, I saw some chromates and flourides could increase cell efficiency but i have only flourides from tap water..
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hissingnoise
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[*] posted on 4-4-2013 at 04:08


There are many threads here on this subject ─ UTFSE!
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Pyro
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[*] posted on 4-4-2013 at 04:12


try YT.
Nurdrage has a video on how to make MnO2 electrodes.
also see his videos on electrochemistry
and woelen's page on electrochemistry:
http://woelen.homescience.net/science/chem/exps/miniature_ch...
http://woelen.homescience.net/science/chem/exps/electrolysis...
google:''how to make a perchlorate cell"
you need dichromate
Please try to look for it before you just ask.




all above information is intellectual property of Pyro. :D
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jock88
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[*] posted on 4-4-2013 at 10:31



You don't need dichromate.
MnO2 electrodes will not make Perchlorate successfully IMO.
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KonkreteRocketry
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[*] posted on 5-4-2013 at 01:50


Quote: Originally posted by Pyro  
try YT.
Nurdrage has a video on how to make MnO2 electrodes.
also see his videos on electrochemistry
and woelen's page on electrochemistry:
http://woelen.homescience.net/science/chem/exps/miniature_ch...
http://woelen.homescience.net/science/chem/exps/electrolysis...
google:''how to make a perchlorate cell"
you need dichromate
Please try to look for it before you just ask.


Thank you, woelen's site is amazing.
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KonkreteRocketry
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[*] posted on 7-4-2013 at 08:31


Ok i got Zinc plates, Tin plates. Does those work?

Btw if i use a 20 Volt circuit , does it do anything ? why does those places mention 5 volt, does the volt really matter a lot ?
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[*] posted on 7-4-2013 at 11:53


The voltage really matters a lot. Don't use 20 volts! The reaction itself requires a very specific voltage (each half-reaction on the anodes and cathodes requires a specific voltage) and added to that, there is overpotential (e.g. due to conversion from liquid to gas) and there is ohmic resistance in the cell. The latter causes conversion of electric power to heat. If you use 20 volts, then
1) your cell will run extremely hot
2) you may destroy your power supply, unless it is a very powerful one or has good shortcircuit protection
3) you will destroy your anode
4) you will have all kinds of undesirable side-reactions which do not produce chlorate.

You can use a higher than 5 volts power supply, but then you need to add series resistors for limiting the current. But if you use 20 volts, then 90% of your power is converted to heat and you will get red hot resistors!




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KonkreteRocketry
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[*] posted on 7-4-2013 at 12:24


Quote: Originally posted by woelen  
The voltage really matters a lot. Don't use 20 volts! The reaction itself requires a very specific voltage (each half-reaction on the anodes and cathodes requires a specific voltage) and added to that, there is overpotential (e.g. due to conversion from liquid to gas) and there is ohmic resistance in the cell. The latter causes conversion of electric power to heat. If you use 20 volts, then
1) your cell will run extremely hot
2) you may destroy your power supply, unless it is a very powerful one or has good shortcircuit protection
3) you will destroy your anode
4) you will have all kinds of undesirable side-reactions which do not produce chlorate.

You can use a higher than 5 volts power supply, but then you need to add series resistors for limiting the current. But if you use 20 volts, then 90% of your power is converted to heat and you will get red hot resistors!


Wow ok, that is lot more than expected. Do you know if i could use Zinc or tin plates for electrolysis ?
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[*] posted on 7-4-2013 at 14:24


You could hook up 4 cells in series to get 5 volts across each one, assuming they are identical. I don't think zinc plates would work very well (they would corrode), but tin might.



As below, so above.
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[*] posted on 7-4-2013 at 23:33


Zinc does not work as anode, nor does tin. Really, you only have very few options:
- platinum, useful for making perchlorate from chlorate. Do not use for making chlorate from chloride!
- MMO, perfect for making chlorate from chloride, not useful for making perchlorate.
- PbO2, can be used for making perchlorate, to some extent also suitable for making chlorate.
- graphite, useful for making chlorate from chloride, but messy (slowly erodes, giving black crud in your solution).

Metals like tin, lead, zinc, aluminium, titanium, silver, tungsten, and so on either quickly dissolve or passivate. MMO anodes are affordable, PbO2 anodes apparently can be made at home, but I have no experience with that and this is not something for the unexperienced, due to the need to work with large amounts of very toxic chemicals. Making perchlorates at home hardly is an option, unless you intend to use a large amount of them. I only needed small quantities for little experiments and then it is better to simply buy them. If you are into pyrotechnics and use kilos per year, then it may be worth investing in platinum anodes and use those to make perchlorate from chlorate.




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[*] posted on 8-4-2013 at 10:26


Quote: Originally posted by woelen  
Zinc does not work as anode, nor does tin. Really, you only have very few options:
- platinum, useful for making perchlorate from chlorate. Do not use for making chlorate from chloride!
- MMO, perfect for making chlorate from chloride, not useful for making perchlorate.
- PbO2, can be used for making perchlorate, to some extent also suitable for making chlorate.
- graphite, useful for making chlorate from chloride, but messy (slowly erodes, giving black crud in your solution).

Metals like tin, lead, zinc, aluminium, titanium, silver, tungsten, and so on either quickly dissolve or passivate. MMO anodes are affordable, PbO2 anodes apparently can be made at home, but I have no experience with that and this is not something for the unexperienced, due to the need to work with large amounts of very toxic chemicals. Making perchlorates at home hardly is an option, unless you intend to use a large amount of them. I only needed small quantities for little experiments and then it is better to simply buy them. If you are into pyrotechnics and use kilos per year, then it may be worth investing in platinum anodes and use those to make perchlorate from chlorate.


I have MnO2, which ive heard is good, but its in powdered form, how shall i turn it into a good electrode ?
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[*] posted on 8-4-2013 at 10:51



I have MnO2, which ive heard is good, but its in powdered form, how shall i turn it into a good electrode ?[/rquote]
You'll need nitric acid, a titanium electrode, a pipette and a hotplate. Given that manganese nitrate decomposes upon heating to MnO2, I'll let you work out the rest.




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[*] posted on 8-4-2013 at 13:12


I don't think it is easy to make an electrode from powdered MnO2. Similarly, I have powdered PbO2 but making an electrode from that is not possible.

Probably you need to start from a manganese(II) salt in solution and use electrolysis at precisely controlled pH using precisely controlled current density in order to electrolytically oxidize the Mn(2+) to MnO2. A similar process is used for making PbO2 anodes from solutions of Pb(NO3)2. This process, however, is very hard to control. You easily get badly adhering layers or powdery deposits on the anode. I think that the MnO2-process is not better than the PbO2-process. Hard to control and extremely difficult to get something useful.




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